Animal models for pah and increased pulmonary blood flow

Abstract

Pulmonary arterial hypertension (PAH), a progressive pulmonary vasoproliferative disorder, is characterized by the development of unique neointimal lesions including concentric laminar intimal fibrosis and plexiform lesions.In PAH associated with congenital heart disease, increased pulmonary blood flow (i.e., systemic-to-pulmonary shunt) is an essential trigger for the occurrence of neointimal lesions and disease development. Although neointimal development is well described histopathologically, the pathogenesis of flow-induced PAH and its typical vascular lesions is largely unknown.Animal models play a crucial part in giving insight in new pathobiological processes in PAH and possible new therapeutic targets. However, as for any preclinical model, the pathophysiological mechanism and clinical course have to be comparable to the human disease that it is supposed to mimic. This means that animal models mimicking human PAH ideally are characterized by (1) a hit resembling the human disease, (2) specific vascular remodeling that resembles neointimal development in human PAH, and (3) progressive disease development that leads to right ventricular (RV) dysfunction and eventually death.Therefore, this chapter will discuss currently used animal models for pulmonary hypertension that are of interest for PAH in the pediatric population, specifically PAH associated with congenital heart disease. Since increased pulmonary blood flow is known to be a trigger for PAH development in this population, particular emphasis will be put on models with increased pulmonary blood flow.